Summary.OPTIC (Observation of Pupils and Teachers in Classrooms) was used to study Hongkong secondary school teachers' use of approval and disapproval and pupils' on‐task behaviour. Despite great individual differences, the sample of teachers was found overall to focus upon pupils' academic behaviour and to emphasise the use of approval. However, disapproval was emphasised as a means of responding to pupils' social behaviour. Positive correlations were found between approval (particularly to academic behaviour) and on‐task behaviour. Negative correlations were found between disapproval (particularly to social behaviour) and on‐task behaviour. In all these respects the findings were similar to those of a recent UK